Hubble - Huge Test For Nasa

The Shuttle Endeavour Is Scheduled To Lift Off Wednesday On A Mission To Repair The Flawed Space Telescope.

November 28, 1993|By Shirish Date of The Sentinel Staff

HOUSTON — Assemble a space station in orbit? No problem. Install parts on broken satellites hundreds of miles in space? Piece of cake.

Such have been NASA's assurances for the past decade, as it lobbied for big-science projects costing billions of dollars. Building and fixing things in orbit was not only doable, the agency said, it was going to become routine.

Early Wednesday, the agency is scheduled to put those assurances to the test when it embarks on what is arguably its most difficult space shuttle mission - to fix the Hubble Space Telescope.

The expensive observatory has numerous ailments, including a manufacturing defect that left it stranded in orbit three years ago with blurred vision.

To cure them all, the crew of the shuttle Endeavour has a laundry list of repair work, from maneuvering a box the size of a refrigerator into the telescope's frame to loosening tiny screws on computer cables.

None of the specific tasks has been tried by spacewalking astronauts in the weightlessness of orbit. Some are crucial if Hubble is to continue working at all.

But the stakes have risen beyond Hubble's fate and the hefty price tags involved - $1.5 billion for the telescope, $283 million for the spare parts and $500 million for the shuttle flight.

If the shuttle Endeavour and its crew succeed, NASA may have proven that, when it applies itself, it can deliver on its promises and even correct earlier shortcomings.

If it fails, the agency could sink a reputation that is taking on water from this year's loss of the billion-dollar Mars Observer and an inability to launch its shuttles in timely fashion.

As the astronauts are saying, it's time for NASA to put up or shut up.

''Now here we are - it needs to be repaired, it needs to be upgraded,'' said Hubble spacewalker Jeff Hoffman, an astrophysicist before he joined NASA. ''We said we could do it - now we have to do it.''

Officially, all shuttle flights are important and difficult, according to NASA. But from the outset, the space agency has treated the Hubble repair mission differently.

The seven astronauts chosen for the flight are veterans - not just veterans of spaceflight but of the particular task each will have to perform during the Hubble mission.

Dick Covey is making his second flight as a shuttle commander, Kenneth Bowersox his second as pilot and Swiss scientist Claude Nicollier his second as operator of the shuttle's robot arm.

''This is a uniquely important mission in the overall scheme of things,'' Hoffman acknowledged recently.

The Hubble mission is the first shuttle flight without ''secondary'' payloads, experiments or tasks. Only a large-format IMAX movie camera has been placed onboard, in case the astronauts find time to document their repair work.

The crew, and the hundreds of ground controllers at Johnson Space Center who will work with them during the flight, have spent almost three times as many hours training for Hubble as for a typical mission.

''Are we training for anything else? No,'' Covey said. ''And do we have time for it? No. And do we have stowage for it? No.''

Even if the company that made Hubble's main mirror had not botched the polishing process, blurring the telescope's vision, chances are Endeavour would be poised on the launch pad this week for a repair mission, anyway.

Not only was Hubble supposed to revolutionize astronomy by placing a high-quality telescope beyond the distorting effects of the atmosphere - it was also to pioneer the placement of long-lasting, maintainable satellites in low-Earth orbit, where shuttles could service them.

Hubble, for instance, was designed with four repair flights in mind: 1993, to replace its Wide-Field Planetary Camera with an updated version; 1996, to replace solar arrays and batteries; 1999, to add instruments; and 2002, to replace the solar panels and batteries again.

The problem is, the repair order for Hubble's first flight has grown longer and more demanding than ever imagined.

Besides the defective mirror, which was discovered shortly after the telescope was placed in orbit in April 1990, Hubble has a growing list of problems.

Chief among them:

Solar panels that jitter each time the telescope passes from sunlight to darkness and vice versa.

Gyroscopes that are breaking down. The telescope needs at least three to aim itself, but three of the six on board are broken. One more, and the telescope is out of action.

Altogether, mission planners have selected 12 items for replacement or repair during Endeavour's mission, which, if necessary, could be extended to 13 days.

They warn that if all seven of the primary repairs are not completed by Endeavour, they will request another repair flight for sometime next year.

Planners first thought they could squeeze all repairs into three days of spacewalking. But a 1992 satellite-repair mission made them change their minds.

The crew aboard Endeavour in May 1992 was supposed to capture and attach a booster rocket to a stranded communications satellite.

But two days were spent attempting to grab the satellite, and NASA wound up authorizing an unprecedented three-person spacewalk to grab it by hand. The operation took three times as long as planned.

That crew - which included Thornton and Akers - discovered there is a big difference between practicing a repair on the ground and doing the real thing in space.

So now the Hubble astronauts are scheduled to make five spacewalks - never before attempted by NASA during a single spaceflight - over five days.

And if things don't go according to plan, the schedule includes time for a sixth and, if necessary, a seventh spacewalk.

''We learned that we're not going to make these timelines by hurrying,'' Akers said recently. There was no way Endeavour's crew could have made all of the Hubble repairs in three days, he added.